1. Field of the Invention
This invention relates generally to a valve device. The valve device is particularly, but not exclusively, suitable for an instrument for preventing outflow of a nosebleed, or for a trachea cannula for supplying an anesthetic into the lung.
2. Description of the Prior Art
The conventional instrument for preventing outflow of a nosebleed is shown in FIG. 1. The instrument comprises an elastic air accumulator or envelope 2 which is able to expand and contract and is attached to one end of a relatively rigid pipe 1 in such a manner that the envelope 2 encloses an open end of the pipe 1. The other end of the pipe 1 is formed with a relatively thick closed portion 1a of silicone rubber. To use the instrument, a needle 3 of an air injector 4 pierces the thick portion 1a as shown in FIG. 1 and the air is forcibly introduced into the pipe 1 with the injector 4. As a result, the air flows into the envelope 2 so that the envelope 2 is elastically expanded by the air pressure as shown by a dot-dash line. When the needle 3 is pulled out of the thick portion 1a, the pin hole formed by the needle 3 in the thick portion 1a closes by elastic restoration, and the air inside is trapped to maintain the envelope 2 expanded.
To use the instrument of FIG. 1 the envelope end is inserted into the nasal cavity. When the envelope 2 reaches the back nasal cavity, it is expanded by the air supplied through the needle 3 of the injector 4. As a result, the expanded envelope 2 tightly contacts a wall surface of the back nasal cavity so that blood entering the nasal cavity as a result of nosebleed cannot flow into the trachea through the back nasal cavity. This enables a nosebleed to be stanched, for example if a hemorrhage occurs during a surgical operation on the nasal cavity.
When the air in the envelope 2 is to be discharged, the needle 3 of the injector 4 is again pierced through the thick portion 1a, so that the air in the pipe 1 can be discharged by the injector 4, or alternatively the thick portion 1a is made as a cap which can be detached from the pipe 1. This is rather troublesome, as a separate instrument (the needle of the injector) or means (the cap) is required for discharging the air.
Again, in the conventional method for measuring an impedance in the middle ear, a detecting element (detecting probe) is inserted into a pipe which can be elastically deformed and is made of, for example, silicone rubber. The pipe with the detecting element is inserted into the concha passage. The pipe has a thick portion in which the detecting element is supported in the concha passage. However, the size of the concha passage varies from person to person, so the detecting element may slip out of the concha passage during the measurement of the impedance or alternatively the pipe may pass painfully on the concha passage.